FIG. 18 illustrates a hydraulic excavator 10, which is a work machine. The hydraulic excavator 10 includes a lower structure 11, an upper structure 12, a cab 13, a work equipment 14, and a power system 15 that includes an engine. The cab 13, the work equipment 14, and the power system 15 are mounted on the upper structure 12, which is rotatably mounted on the lower structure 11. The power system 15 is covered by a top cover 16, side doors 17,18, and other such components. The side doors 17,18 are mounted by hinges, which will be explained later, so as to be capable of opening and closing, and secured in the closed state by means of a latching device 19.
Examples of conventional side doors 17,18 of a work machine include a door panel with a double-panel structure including an outer panel and an inner panel. When producing such a door panel, the inner panel is fixed to the outer panel by the adhering strength of an adhesive, and the adhering surfaces of the outer panel and the inner panel to which the adhesive is applied are uniformly flat surfaces (e.g. See Japanese Laid-open Patent Publication No. 9-228412 (page 3, and FIG. 7)).
As the adhering surfaces of the outer panel and the inner panel of the conventional side door described above are flat surfaces, the adhesive may become completely flattened at some areas where there is little remaining adhesive, resulting in reduction in the adhering strength of the adhesive.
This presents a particularly serious problem in the case of a door designed with high-heat tolerance, because such a door requires openings, and the region around the openings is prone to not only reduction in the strength but also reduction in the remaining area of the adhering surfaces, making it difficult to maintain the adhering strength of the adhesive and impairing the integrity of the entire door panel.
In order to solve the above problems, an object of the invention is to provide a door panel that is capable of maintaining the adhering strength of the adhesive. Another object of the invention is to provide a door panel that includes openings for high-heat resistance and is capable of maintaining the adhering strength of the adhesive and preventing reduction in the strength around the openings.